The invention is directed to a marine navigation light system. Such systems generally include a number of lamp stations mounted on an artificial offshore structure or platform. In the past, such lamp stations have been controlled by a centrally located logic controller comprising discrete logic components. Each station would for example have one or two ac lamps each configured to separately produce "15 mile" light and a single dc standby lamp for producing "10 mile" light. During normal operation, one "15 mile" ac lamp at each station would be flashed in an on/off pattern so as to create a visible Morse code designating a particular letter of the alphabet. If one of the ac lamps would malfunction during normal operation, the controller would switch off all ac lamps, at all stations, and start operating dc standby lamps at the stations while setting off an alarm. Typically, the controller was mounted in a central location which necessitated running many large gauge wires over long distances to power the station lamps.
In the past, marine navigation light systems included lamp stations which were specially configured to meet but not exceed the requirements of a specific country or regulatory body. For example, so-called "North Sea" requirements specify two "15 mile" lamp stations positioned at diametrically opposed platform corners. Also, each such station had to be provided with a "10 mile" dc standby lamp. The two other platform corners had to be provided with "3 mile" red lamps. The failure of the ac lamp(s) at a "15 mile" station would therefore prevent the station from generating "15 mile" light. The station's "10 mile" dc lamp was provided only as a standby lamp in the event of loss of the ac lamp(s) so that the station could switch from "15 mile" light to "10 mile" light operation. Thus, the dc standby lamps were utilized during normal operation to generate the same on/off pattern as the ac lamps. This posed a significant drain on available dc power. The same parameters are generally specified in the so-called "Dutch Waters" requirements except that "10 mile" dc lamps are substituted for the "3 mile" red lamps.
The problem solved by the present invention is that of providing a universal marine navigation light system capable of being conveniently configured to meet and actually exceed all international marine light navigation system requirements including "North Sea" and "Dutch Waters" requirements, without having to run a large number of controller cables over long distances to control the lamp stations. Applicants' solution is a marine light navigation system built on a fundamental building block in the form of a universal lamp station having a dedicated microcomputer control wherein normal operation takes place at all times under ac power thereby avoiding dc power drain. Each such lamp station is capable of "15 mile" operation off the ac line despite the failure of an ac lamp and "12 mile standby" operation also off the ac line despite the failure of two ac lamps. Operation off a dc supply is only required to generate a "default" signal wherein normal operation is no longer possible. The dedicated microcomputer control enormously simplifies the wiring requirements to operate each station and permits any number of such stations to be interconnected in a communications loop so as to guarantee synchronous operation of all stations. As a result, the same light characteristics are presented in all directions of view with respect to the platform. The attendant reduction in hardware and wiring permits each microcomputer control to be mounted in a relatively small, explosion-proof enclosure so that the station can be installed and operated in potentially hazardous areas. The dedicated microcomputer control also enables the status of all ac lamps to be monitored virtually continuously during operation in "on" intervals as well as "off" intervals of a flash sequence.